Lone Quail Space Requirements?

I posted a few days ago about the 2 male quail dilemma. I think we'll keep the 2 quail, but will need to get another cage until I can build their permanent homes.

I know all you quail lovers have many more on your hands than just 2 little guys, but could you give me an idea of how small I could go in terms of a cage for a lone quail? What is the minimum height I should give him? I've already got one in the cage that is 22X18, it is about 19" high in terms of the usable space for the bird and I'd prefer it if I didn't have to buy another one that size, due to space restrictions in the house, but I don't want to make the guy suffer.

As for their future homes, I'm looking at making mini-coops with attached runs for them that would be portable so I could rotate them around the yard and garden. I'm working off the assumption that the coops themselves wouldn't need to be very big at all, given they are for one small bird. I am feeling most inspired by the following coops (hope you don't mind me posting these questions here, since they are quail-specific!)

This one here at BYC, in a modified and mini-version, with the slope of the roof reversed and an indoor wire floor added over a droppings pan, because I'm finding that's such a convenience on the cage we have: https://www.backyardchickens.com/coops/edlup.html

My other idea would be a modification on the A-Frame theme found in both these coops:

Obviously, they would need to be smaller than the Catawba Coop, but I kind of dig the upper-story residence and lower run. Would having airspace under the "house" be too drafty for the little guys? http://www.catawbacoops.com/

Cool theres a coop named after my ole rabbitry name and my quails website/pedigree name (catawba) then again I named them all after the indians that traversed through our property on their pilgirmage south. I was going to name them after my own indian blood "Crow" but i thought that'd sound silly "Crow Coturnix" HA HA!!!! So it's "Catawba's Coturnix"

Well if you put them on the ground, you may want to worm them, and since you're not eating them being on the ground wont matter much other than worming them every now and then because they will pick up ickies.

One coturnix wont need all that much room at all. it's something like 1-2 sf per bird (i forget the exact), so anyting bigger than that for such a small number of birds per cage (*cough* one *cough* he he) would be a mansion for them I can see it now, the worlds most pampered quails!

Edited to add: You do not need really ANY height at all for coturnix......and actually, it's better in the long run to have short ceilings for coturnix quails as they can bonk and break their necks if they have a lot of ceiling area to forcibly fly into. My pens are like 2 ft high ceilings, im lucky my coturnix in there arent jumpy but some are and 2 ft has killed some peoples coturnix quail. In mass breeding facilities for coturnix quails in japan, the birds are in like 1ft high pens.

Quote:my youngsters I still have in the house were flinging out of the tote brooder, until i finnally got fed up with it and put them ina 10 gallon tank, they're doing wonderfully in there and for some reason they dont bop in it lol! It's only 1ft high....therse 6 birds in there you'd think that'd be cramped it really isnt, i've never seen such happy birds lol!

I had a hatch of A&M's that ended up being both males (2). One lives in a cage that is about 6"wide by 10"long, the other shares a 10 gallon fish tank with a male button quail. They seem to be happy, other than the one being alone. He is always chattering at the other 2. The two A&M's had started fighting at about 5 weeks old, and have been seperated for at least a month.